Display device and method of fabricating the same

ABSTRACT

A method of fabricating a driver circuit for use with a passive matrix or active matrix electrooptical display device such as a liquid crystal display. The driver circuit occupies less space than heretofore. A circuit (stick crystal) having a length substantially equal to the length of one side of the matrix of the display device is used as the driver circuit. The circuit is bonded to one substrate of the display device, and then the terminals of the circuit are connected with the terminals of the display device. Subsequently, the substrate of the driver circuit is removed. This makes the configuration of the circuit much simpler than the configuration of the circuit heretofore required by the TAB method or COG method, because conducting lines are not laid in a complex manner. The driver circuit can be formed on a large-area substrate such as a glass substrate. The display device can be formed on a lightweight material having a high shock resistance such as a plastic substrate. Hence, a display device having excellent portability can be obtained.

BACKGROUND OF THE INVENTIONS

1. Field of the Invention

The present invention relates to a passive matrix or active matrixdisplay such as a liquid crystal display and, more particularly, to afashionable display device in which the ratio of the area of the displayportion to the area of the substrates of the display device is increasedby effectively mounting a driver semiconductor integrated circuit.

2. Description of the Related Art

Passive matrix type and active matrix type constructions are known asmatrix display devices. In the passive matrix type, a number ofstripe-shaped conducting lines (row lines) made of a transparentconductive film or the like are arrayed in a certain direction on afirst substrate. On a second substrate, similar stripe-shaped conductinglines (column lines) are arrayed in a direction substantiallyperpendicular to the conducting lines on the first substrate. Bothsubstrates are so arranged that the conducting lines on them intersecteach other.

An electrooptical material such as a liquid crystal material whosetransparency, reflectivity, or scattering performance is varied by avoltage, current, or the like is positioned between both substrates. Ifa voltage or current is applied between an addressed row line on thefirst substrate and an addressed column line on the second substrate,then the transparency, reflectivity, or scattering performance at theintersection can be set to a desired value. In this way, the displaydevice can be matrix driven.

In the active matrix construction, row and column lines are formed onthe first substrate by multilayer metallization techniques. Pixelelectrodes are formed at the intersections of the row and column lines.An active device such as a thin-film transistor (TFT) is formed at eachpixel electrode to control the potential or current in the pixelelectrode. A transparent conductive film is also formed on the secondsubstrate. Both substrates are so arranged that the pixel electrodes onthe first substrate are located opposite to the transparent conductivefilm on the second substrate.

In either type, the substrates are selected according to the usedprocess. For example, the passive matrix construction needs no complexprocess steps except for steps where the transparent conductive filmsare formed and etched into row and column conducting line patterns. Thesubstrates of this passive matrix type may be made from plastic, as wellas from glass. On the other hand, to manufacture the active matrixconstruction, a relatively high-temperature film formation step isrequired. Furthermore, the active matrix type must keep out mobile ionssuch as sodium ions. The substrates of the active matrix type must bemade of glass containing a quite low concentration of alkali.

In any type of prior art matrix display device excluding specialconstructions, a semiconductor integrated circuit (peripheral drivercircuit) for driving the matrix is required to be mounted. In the past,this has been done by tape automated bonding (TAB) or chip on glass(COG). However, the matrix construction contains as many as severalhundreds of rows. Therefore, the integrated circuit has a very largenumber of terminals. The corresponding driver circuit takes the form ofa rectangular IC package or semiconductor chip. To connect theseterminals with the conducting lines on the substrates, it is necessaryto lay the conducting lines in a complex manner. As a consequence, theratio of the area of the peripheral portion, or non-display portion, tothe area of the display portion is not negligibly small.

A method for solving this problem is disclosed in Japanese PatentLaid-Open No. 14880/1995, and consisting of forming a driver circuit onan elongated substrate (referred to as a stick or stick crystal) havinga length substantially equal to one side of the matrix construction andconnecting the driver circuit with the terminal portion of the matrix.This arrangement is permitted, because a width of about 2 mm sufficesfor the driver circuit. Therefore, almost the whole area of thesubstrate can be made a viewing screen.

Of course, in this case, where the matrix has a large area, it isimpossible to form a circuit on a silicon wafer. Consequently, it isnecessary to form the circuit on a glass substrate or the like. Hence,active devices used in semiconductor devices are TFTs.

However, where a stick crystal is employed, the thickness of thesubstrate of the driver circuit has been an obstacle to miniaturizationof the whole display device. For example, where the display deviceshould be made thinner, the thickness of the substrate is allowed to beset to 0.3 mm by optimizing the kind of the substrate and themanufacturing steps. However, because of the strength necessary duringmanufacturing steps, it is difficult to reduce the thickness of thestick crystal below 0.5 mm. As a result, where two substrates are bondedtogether, the stick crystal protrudes as long as 0.2 mm or more.

Furthermore, if the stick crystal differs from the substrates of thedisplay device in kind, then defects may be produced in the circuitbecause of the difference in coefficient of thermal expansion and forother causes. Especially, where a plastic substrate is used in a displaydevice, this problem is conspicuous, because poor heat resistance ofplastics makes it substantially impossible to use a plastic substrate asa stick crystal substrate.

Moreover, where the kind of the substrate supporting the stick crystalis different from the kind of the substrates of the display device,other known methods are used to circumvent the above-described problem.In one known method, a semiconductor integrated circuit having TFTs isfabricated on other support substrate. Then, the circuit is peeled offand adhesively bonded to another substrate. In another known method, theoriginal support substrate is removed after adhesively bonding thecircuit to another substrate. This technique is generally known assilicon-on-insulator (SOI) technique.

However, when the support substrate is removed, the semiconductorintegrated circuit is often damaged, thus deteriorating themanufacturing yield.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a smaller displaydevice of reduced weight by solving the foregoing problems with thestick crystal.

It is another object of the invention to provide a method of fabricatingdisplay devices with a high production yield by solving theaforementioned problems.

The present invention is characterized in that the driver circuitportion of a display device is made thinner by mechanically bonding asemiconductor integrated circuit equivalent to a stick crystal to asubstrate for the display device, making electrical connections, andthen removing only the substrate from the stick crystal. In thisconstruction, stress induced by deformation caused by thermal expansionof the substrate is applied uniformly to the whole circuit. Therefore,the stress is prevented from being concentrated in certain portions;otherwise it would be inevitable that defects are produced.

Essentially, the present invention lies in a display device comprising afirst substrate and a second substrate having a transparent conductivefilm on its surface. Conducting lines are formed on the first substrate.The first substrate has an elongated semiconductor integrated circuitwhich is electrically connected with the conducting lines and has TFTs.The transparent conductive film on the second substrate faces thesurface of the first substrate on which the conducting lines are formed.The length of the semiconductor integrated circuit is roughly equal tothe length of one side of the viewing surface, or the matrix, of thedisplay device, in the same way as the stick crystal described in theabove-cited Japanese Patent Laid-Open No. 14880/1995. The semiconductorintegrated circuit is first fabricated on another substrate. Theintegrated circuit is peeled off and mounted on the first substrate.

In the case of the passive matrix type, the display device comprises afirst substrate having an elongated first semiconductor circuit and asecond substrate having a second semiconductor integrated circuit. Aplurality of first conducting lines extending in a first direction areformed from a transparent conductive film on the first semiconductorintegrated circuit. The first semiconductor integrated circuit isconnected with the first conducting lines, has TFTs, and extends in asecond direction substantially perpendicular to the first direction. Thesecond substrate has second conducting lines which are formed from atransparent conductive film and extend in the second direction. Thesecond semiconductor integrated circuit is connected with the secondconducting lines, has TFTs, and extend in the first direction. The firstand second substrates are so arranged that the first conducting linesare located opposite to the second conducting lines. The first andsecond semiconductor integrated circuits are obtained by fabricatingthem on other substrates, peeling the integrated circuits off, andbonding them to their respective substrates.

In the case of an active matrix type, the display device comprises afirst substrate having a first and a second semiconductor integratedcircuits and a second substrate having a transparent conductive film onits surface. A plurality of first conducting lines extending in a firstdirection are formed on the first substrate. The first semiconductorintegrated circuit is connected with the first conducting lines, hasTFTs, and extend in a second direction substantially perpendicular tothe first direction. A plurality of second conducting lines extending inthe second direction are formed also on the first substrate. The secondsemiconductor integrated circuit is connected with the second conductinglines, has TFTs, and extends in the first direction. The first andsecond substrates are so arranged that the first and second conductinglines on the first substrate are opposite to the transparent conductivefilm on the second substrate. The first and second semiconductorintegrated circuits are obtained by fabricating them on othersubstrates, peeling the integrated circuits off, and mounting them tothe first substrate.

The method consisting of forming a semiconductor integrated circuithaving TFTs on other substrate, peeling off the circuit, and bonding thecircuit to a further substrate (alternatively, the original substrate isremoved after bonding to another substrate) is generally known as one ofSOI (silicon-on-insulator) techniques and described in Japanese PatentLaid-Open No. 504139/1994. Also, other well-known techniques can beused.

The step for peeling a semiconductor integrated circuit from its supportsubstrate needs the most advanced technique. The present invention ischaracterized in that when the semiconductor integrated circuit ispeeled from the support substrate, a gas containing a halogen,especially halogen fluoride, is used.

A halogen fluoride is given by a chemical formula XF_(n), where X is ahalogen other than fluorine and n is an integer. It is known thathalogen fluorides include chlorine monofluoride (ClF), chlorinetrifluoride (ClF₃), bromine monofluoride (BrF), bromine trifluoride(BrF₃), iodine monofluoride (IF), and iodine trifluoride (IF₃).

A halogen fluoride is characterized in that it etches silicon even undera non-plasma state but does not etch silicon oxide at all. Since it isnot necessary to use a plasma, the circuit is not destroyed by plasmadamage. This effectively contributes to an improvement in the productionyield. Furthermore, the etching selectivity between silicon oxide andsilicon is quite high. This is advantageous in that neither the circuitnor the elements are destroyed.

In the present invention, a peeling layer consisting principally ofsilicon is formed on a support substrate. A semiconductor integratedcircuit coated with silicon oxide is formed on the peeling layer. Asmentioned above, silicon is etched by a halogen fluoride without using aplasma. Other gases containing a halogen such as carbon tetrafluoride(CF₄) and nitrogen trifluoride (NF₃) etch silicon under a plasmacondition and so they can be used for the invention.

Accordingly, by placing the support substrate either within a gascontaining a halogen such as a halogen fluoride or within a plasma, thepeeling layer is peeled from the support substrate. As a consequence,the semiconductor integrated circuit can be peeled off.

An example of a display device according to the present invention isshown in FIGS. 1(A)-1(D) in cross section. FIG. 1(A) depicts the devicewith a relatively small magnification. The left side of this figureshows a driver circuit portion 7 having a semiconductor integratedcircuit 2. The right side shows a matrix portion 8. A conducting linepattern 4 is formed from a transparent conductive film on a substrate 1.A bump 6 is made of gold or other similar material. The semiconductorintegrated circuit 2 has a thickness substantially equal to thethickness of TFTs. The integrated circuit 2 has a connector portionhaving an electrode 5 made of a conductive oxide whose contactresistance is not varied if it is oxidized. The electrode 5 is broughtinto contact with the bump 6. A resin 3 is injected between thesemiconductor integrated circuit 2 and the substrate 1 to mechanicallyhold the components (FIG. 1(A)).

FIG. 1(B) is an enlarged view of the contact portion surrounded by thedotted line in FIG. 1(A). It is to be noted that like components areindicated by like reference numerals in various figures. FIG. 1(C) is anenlarged view of the portion surrounded by the dotted line in FIG. 1(B).The semiconductor integrated circuit includes an N-channel TFT 12 and aP-channel TFT 13 which are sandwiched by a buffer dielectric film 11 andan interlayer dielectric layer 14 and a passivation film 15 made ofsilicon nitride or the like (FIGS. 1(B) and 1(C)).

When a semiconductor integrated circuit is formed, the buffer film 11 isnormally made of silicon oxide. However, sufficient moisture resistancecannot be obtained only with this scheme. Therefore, a passivation filmmust be formed on the buffer film. If the semiconductor circuit and itscontact portion are thinner than the spacing between the substrates ofthe device as shown in FIG. 3, then it is possible to form a countersubstrate 16 on the circuit. In this case, the outer side of the drivercircuit portion 7 is sealed with a sealing material 17 such as epoxyresin, in the same way as the manufacture of a liquid crystal device asdisclosed in Japanese Patent Laid-Open No. 66413/1993. The gap betweenthe substrates 1 and 16 is filled with a liquid crystal material 18 andso mobile ions do not intrude into the gap from the outside. Hence, anyspecial passivation film is not required (FIG. 3).

The contact portion can use a bump as described above. Another method isillustrated in FIG. 1(D). That is, conductive particles 9 such asparticles of gold are diffused into the contact portion to provideelectrical contact. The diameter of the particles is slightly greaterthan the spacing between the semiconductor integrated circuit 2 and thesubstrate 1 (FIG. 1(D)).

The sequence for fabricating this display device which is of the passivematrix type is shown in FIGS. 2(A)-2(G). First, a number ofsemiconductor integrated circuits 22 are formed on an appropriatesubstrate 21 (FIG. 2(A)).

The resulting laminate is cut to form stick crystals 23 and 24. Theelectrical characteristics of the obtained stick crystals 23 and 24 maybe checked before the next manufacturing step is effected, to judgewhether the crystals are acceptable or rejected (FIG. 2(B)).

Then, the surfaces of the stick crystals 23 and 24 on which the circuitsare formed are bonded to surfaces 26 and 28 of separate substrates 25and 27, respectively. Conducting line patterns are formed fromtransparent conductive films on the surfaces 26 and 28. Electricalconnections are made (FIGS. 2(C) and 2(D)).

Subsequently, the stick drivers 23 and 24 are peeled from theirrespective substrates by SOI techniques or by processing with a gascontaining a halogen. In this way, only semiconductor integratedcircuits 29 and 30 are left on the surfaces 26 and 28, respectively, ofthe substrates (FIGS. 2(E) and 2(F)).

Finally, the laminates obtained in this manner are made to face eachother. As a result, a passive matrix display is derived. A surface 26faces away from the surface 26. That is, no conducting line pattern isformed on the surface 26 (FIG. 2(G)).

In the above example, the row stick crystal (i.e., the stick crystal fora driver circuit for driving row lines) and the column stick crystal(i.e., the stick crystal for a driver circuit for driving column lines)are extracted from the same substrate 21. Of course, they may beextracted from separate substrates.

The example shown in FIGS. 2(A)-2(G) is a passive matrix display.Obviously, the invention can be similarly applied to an active matrixdisplay. In the illustrated examples given below, each substrate is madeof a filmy material.

Other objects and features of the invention will appear in the course ofthe description thereof, which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(A)-1(D) are cross-sectional views of a display device accordingto the present invention;

FIGS. 2(A)-2(G) are exploded perspective views of another display deviceaccording to the invention, schematically illustrating a method offabricating the device;

FIG. 3 is a cross-sectional view of a further display device accordingto the invention;

FIGS. 4(A)-4(C) are cross-sectional views of a stick crystal used formanufacturing steps according to the invention;

FIGS. 5(A)-5(D) are cross-sectional views, illustrating steps forbonding a stick crystal to a substrate; and

FIG. 6 is a schematic view of a system for fabricating filmy liquidcrystal devices in succession.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

Manufacturing steps for fabricating one substrate of a passive matrixliquid crystal display are briefly described now. The present example isdescribed by referring to FIGS. 4(A)-4(C) and 5(A)-5(D). Steps forforming a driver circuit on a stick crystal are schematically shown inFIGS. 4(A)-4(C). Steps for mounting the stick crystal on the substrateof the liquid crystal display are schematically shown in FIGS.5(A)-5(D).

First, a silicon film having a thickness of 3000 Å was deposited as apeeling layer 32 on a glass substrate 31. Since the silicon filmbecoming the peeling layer 32 is etched away when circuitry and asubstrate formed on the silicon film are separated, the quality of thesilicon film will present almost no problems. Therefore, the siliconfilm may be deposited by a method which permits mass production.Furthermore, the silicon film may be either amorphous or crystalline incharacter.

The glass substrate may be made of Corning 7059 glass, Corning 1737glass, NH Technoglass NA45, NH Technoglass NA35, Nippon Denki Glass OA2,other non-alkali or low-alkali glass, or quartz glass. Where quartzglass is used, the cost poses a problem. In the present invention,however, the area of the substrate used in one liquid crystal display isquite small and so the cost per device is sufficiently low.

A silicon oxide film was deposited as a buffer film 33 having athickness of 5000 Å on the peeling layer 32. Sufficient care must betaken in fabricating the buffer film 33 from silicon oxide. Islands 34and 35 of crystalline silicon region were formed by a well-known method.The thickness of the islands of crystalline silicon region greatlyaffects the required semiconductor characteristics. Generally, it wasdesired to make the thickness smaller. In the present example, thethickness was 400-600 Å.

Where crystalline silicon is obtained, laser annealing (i.e., amorphoussilicon is illuminated with intense light such as laser light) orsolid-phase epitaxy using thermal annealing is employed. Wheresolid-phase epitaxy is utilized, if a catalytic element such as nickelis added to the silicon as disclosed in Japanese Patent Laid-Open No.244104/1994, then the crystallization temperature can be lowered, andthe annealing time can be shortened. Furthermore, as described inJapanese Patent Laid-Open No. 318701/1994, once silicon is crystallizedby solid-phase epitaxy, it may be laser-annealed. The adopted method isdetermined, taking account of the required semiconductor circuitcharacteristics, the maximum processing temperature of the substrate,and other factors.

Then, a gate-insulating film 36 of silicon oxide having a thickness of1200 Å was deposited by plasma CVD or thermal CVD. Subsequently, gateelectrodes/interconnects 37, 38 were formed from a crystalline siliconfilm having a thickness of 5000 Å. The gate electrodes/interconnects 37,38 may be made from metals such as aluminum, tungsten, and titanium, ortheir silicides. Where metallic gate electrodes/interconnects 37, 38 areformed, their top or side surfaces may be coated with anodic oxide asdisclosed in Japanese Patent Laid-Open Nos. 267667/1993 and 338612/1994.The material of the gate electrodes/interconnects 37, 38 is determinedaccording to the required semiconductor circuit characteristics, themaximum processing temperature of the substrate, and other factors (FIG.4(A)).

Thereafter, N- and P-type impurity ions were introduced into the islandsof silicon 34 and 35 by self-aligned ion implantation or other method toform N-type regions 39 and P-type regions 40. Then, an interlayerdielectric film 41 of silicon oxide having a thickness of 5000 Å wasdeposited by a well-known means. Contact holes were created in thisinterlayer dielectric film. Aluminum alloy interconnects 41-44 wereformed (FIG. 4(B)).

A silicon nitride film 46 having a thickness of 2000 Å was deposited asa passivation film on the laminate by plasma CVD. Contact holescommunicating with the output terminal lines 44 were formed in thispassivation film. An ITO (indium-tin oxide) electrode 47 having athickness of 1000 Å was formed by sputtering techniques. ITO is atransparent conductive oxide. A gold bump 48 having a diameter of about50 μm and a height of 30 μm was mechanically formed on the ITO electrode47. The resulting circuit was cut into appropriate size, thus obtaininga stick crystal (FIG. 4(C)).

An electrode 50 was formed also from ITO to a thickness of 1000 Å onanother substrate 49 of the liquid crystal display. In the presentexample, a substrate of polyethylene sulfite having a thickness of 0.3mm was used. The substrate 31 of the stick driver was bonded to thissubstrate 49 under pressure. At this time, the electrodes 47 and 50 wereelectrically connected to each other via the bump 48 (FIG. 5(A)).

Then, an adhesive 51 to which a thermosetting organic resin was addedwas injected into the gap between the stick crystal 31 and the substrate49 of the liquid crystal display. The adhesive may be applied to thesurface of any one of the stick crystal 31 and the substrate 49 beforethey are bonded together under pressure.

The laminate was processed for 15 minutes in an oven filled with anitrogen ambient at 120° C. In this way, electrical connection andmechanical bonding between the stick crystal 31 and the substrate 49were completed. Before the bonding operation is completed in this way, acheck may be done to see whether the electrical connection issatisfactory or not by the method disclosed in the above-cited JapanesePatent Laid-Open No. 14880/1995 (FIG. 5(B)).

The laminate processed in this way was allowed to stand in a stream ofmixture gas of chlorine trifluoride (ClF₃) and nitrogen. The flow rateof each of the chlorine trifluoride and nitrogen was 500 SCCM. Thereaction pressure was 1 to 10 torr. The temperature was roomtemperature. It is known that halogenated fluorine such as chlorinetrifluoride selectively etches silicon. On the other hand, oxides suchas silicon oxide and ITO are hardly etched. Also with respect toaluminum, if a stable oxide coating is formed on an aluminum film, thenreaction no longer progresses. Hence, the aluminum is not etched.

In the present example, materials which might be attacked by chlorinetrifluoride are the peeling layer (silicon) 32, the islands of silicon34, 35, the gate electrodes/interconnects 37, 38, the aluminum alloyinterconnects 41-44, and the adhesive 51. These materials excluding thepeeling layer 32 and the adhesive 51 are capped with silicon oxide andother materials and, therefore, chlorine trifluoride is unable to reachthem. In practice, only the peeling layer 32 was selectively etched asshown in FIG. 5(C), thus forming voids 52.

As time passed further, the peeling layer 32 was completely etched away,so that the bottom surface 53 of the buffer film 33 was exposed. Thus,the substrate 31 of the stick crystal was separated from thesemiconductor circuit. With etching using chlorine trifluoride, theetching process came to a stop at the bottom surface of the buffer filmand so the bottom surface 53 was quite flat (FIG. 5(D)).

In this manner, fabrication of the semiconductor integrated circuit onone substrate of the liquid crystal display was completed. The liquidcrystal display is completed, using the substrate obtained in this way.

EXAMPLE 2

The present example relates to a method (referred to as the roll-to-rollmethod) of successively fabricating filmy passive matrix liquid crystaldisplays. A production system for implementing the present example isshown in FIG. 6. The substrate material for obtaining the filmy liquidcrystal displays may be selected from polyethylene sulfite,poly-carbonate, and polyimide. Since polyethylene terephthalate andpolyethylene naphthalate are polycrystalline plastics, they are notappropriate as liquid crystal materials which provide displays makinguse of polarization of light.

The production system shown in FIG. 6 is divided into two major parts:the upper portion and the lower portion. In the lower portion, asubstrate on which color filters are formed is fabricated as a componentof a liquid crystal display. In the upper portion, a counter substrateis manufactured. First, steps for fabricating the substrate on which thecolor filters are formed are described.

Color filters of the three primary colors (RGB) are printed on thesurface of a film wound on a roll 71. The color filters are formed,using three sets of rolls 72. Where the manufactured liquid crystaldisplays are monochrome devices, this step is dispensed with. This stepis referred to as color filter printing.

Then, an overcoat is printed to form a planarization film, using rolls73. The overcoat acts to planarize the surface which is made uneven bythe formation of the color filters. A transparent resinous material maybe used as the material of the overcoat. This step is referred to asprinting of overcoat (planarization film).

Then, row (column) electrodes are printed in a desired pattern, using aconductive ink, by means of rolls 74. This step is referred to asformation of electrodes.

Thereafter, an orientation film is printed, using rolls 75. This step isreferred to as printing of orientation film. The film is passed througha heating furnace 76 to bake and solidify the orientation film. Thisstep is referred to as the baking of orientation film.

The film is then passed between rolls 77 to rub the surface of theorientation film. In this way, the orientation step is completed. Thisstep is referred to as rubbing.

Then, a stick crystal is mounted on the substrate by a pressureconnection device 78. This step is referred to as mounting of the stickcrystal. The laminate is passed through a heating furnace 79 to cure theadhesive. Thus, the bonding operation is completed. This step isreferred to as curing of the adhesive.

In the present example, the peeling layer uses silicon, in the same wayas in Example 1. Then, the peeling layer is etched by a chlorinetrifluoride chamber 80 which is differentially pumped to prevent thechlorine trifluoride from leaking out. As a result, the substrate ispeeled from the stick crystal. This step is referred to as peeling ofthe stick crystal.

Then, spacers are sprayed onto the filmy substrate by a spacerapplicator 81. This step is referred to as spraying of spacers. Asealing material is printed, using rolls 82. The sealing material actsto bond together the two opposite substrates and to prevent the liquidcrystal material from leaking from the space between the substrates. Inthe present example, the semiconductor circuit is rendered thinner thanthe spacing between the substrates to seal the outer surface of thesemiconductor integrated circuit as shown in FIG. 3, as disclosed in theabove-cited Japanese Patent Laid-Open No. 66413/1993. This step isreferred to as printing of the sealant.

Subsequently, a liquid crystal material is dripped, using a liquidcrystal dripper 83. As a result, a liquid crystal material layer isformed on the filmy substrate. In this way, the substrate on the side ofthe color filters, or a color filter panel, is completed. Thesemanufacturing steps are made to progress successively by rotating thevarious rolls.

Then, steps for manufacturing the counter substrate are described.Column (row) electrodes are formed in a desired pattern on the filmysubstrate fed out of a roll 61 by means of rolls 62. This step isreferred to as formation of electrodes.

Thereafter, an orientation film is formed by printing techniques, usingrolls 63. This step is referred to as printing of the orientation film.The film is passed through a heating furnace 64 to bake and solidify theorientation film. This step is referred to as baking of the orientationfilm.

Then, the filmy substrate is passed between rolls 65 to orient themolecules of the liquid crystal material. This step is referred to asrubbing.

The stick crystal is mounted on the substrate by a pressure connectiondevice 66. This step is referred to mounting of the stick crystal. Thelaminate is passed through a heating furnace 67 to cure the adhesive.This step is referred to as curing of the adhesive.

Then, the substrate of the stick crystal is peeled off by a chlorinetrifluoride chamber 68. This step is referred to as peeling of the stickcrystal.

The filmy substrate undergone the steps described thus far is passedaround a roll 69 and sent to next rolls 84. The substrate having thecolor filters and the counter substrate are bonded together by the rolls84, thus forming a liquid crystal cell. This step is referred to asbonding.

The assembly is then heated by a heating furnace 85 to cure the sealingmaterial. In this way, the bonding of the substrates is completed. Thisstep is referred to as curing of the sealant.

The assembly is cut into desired dimensions by a cutter 86, thuscompleting a filmy liquid crystal display. This step is referred to ascutting.

In the present invention, the kinds, the thickness, and the size of thesubstrates of the display device can be varied variously. For example,as described in Example 2, a liquid crystal display in the form of aquite thin film can be obtained. In this case, the display device may becurved along a curved surface and bonded to it. Furthermore, lessrestrictions are imposed on the kind of the substrates. As aconsequence, a lightweight material having high shock resistance such asa plastic substrate may also be used. This improves the portability.

In addition, in the present invention, the semiconductor integratedcircuit forming a driver circuit is peeled from its support substrate bya halogen-containing gas which is not in a plasma state. Therefore,destruction of the semiconductor integrated circuit which would normallybe caused by plasma damage can be prevented. This leads to animprovement in the yield with which liquid crystal displays aremanufactured.

Moreover, the driver circuit occupies less area and so the displaydevice can be arranged relative to other devices with a greater degreeof freedom. Typically, the driver circuit can be confined within aregion only a few centimeters wide around the display surface.Therefore, the display device itself is quite simple and is a highlyfashionable industrial product. It can find extensive application.Hence, the present invention is industrially quite advantageous.

1. A method of manufacturing a display device comprising: forming acolor filter over a first substrate; forming a planarization film overthe color filter; forming an electrode over the planarization film;forming an orientation film over the electrode; providing a drivercircuit over the first substrate with an adhesive therebetween, saiddriver circuit held by a second substrate; removing said secondsubstrate holding said driver circuit over the first substrate tomaintain said driver circuit over the first substrate; forming a sealingmaterial over the first substrate; dripping a liquid crystal materialonto the orientation film; bonding a counter substrate to the firstsubstrate with said liquid crystal material interposed therebetween bysaid sealing material; and cutting the bonded first and countersubstrates.
 2. The method according to claim 1 wherein said displaydevice is a passive type display device.
 3. The method according toclaim 1 wherein said display device is an active matrix display device.4. A method of manufacturing an active matrix display device comprising:forming an electrode over a first substrate; forming an orientation filmover the electrode; providing a driver circuit over the first substratewith an adhesive therebetween, said driver circuit held by a secondsubstrate; removing said second substrate holding said driver circuitover the first substrate to maintain said driver circuit over the firstsubstrate: forming a sealing material over the first substrate; drippinga liquid crystal material onto the orientation film; bonding a countersubstrate to the first substrate with said liquid crystal materialinterposed therebetween by said sealing material; and cutting the bondedfirst and counter substrates.
 5. The method according to claim 1 whereinthe first substrate is a flexible substrate.
 6. The method according toclaim 4 wherein the first substrate is a flexible substrate.
 7. A methodof manufacturing a display device comprising: forming a color filterover a first substrate; forming a planarization film over the colorfilter; forming an electrode over the planarization film; forming anorientation film over the electrode; providing a driver circuit over thefirst substrate with an adhesive therebetween, said driver circuit heldby a second substrate; removing said second substrate holding saiddriver circuit over the first substrate to maintain said driver circuitover the first substrate; forming a sealing material over the firstsubstrate wherein the driver circuit is located in a region surroundedby the sealing material; dripping a liquid crystal material onto theorientation film; bonding a counter substrate to the first substratewith said liquid crystal material interposed therebetween by saidsealing material; and cutting the bonded first and counter substrates,wherein the driver circuit is located between the first and countersubstrates.
 8. The method according to claim 7 wherein said displaydevice is a passive type display device.
 9. The method according toclaim 7 wherein said display device is an active matrix display device.10. The method according to claim 1 wherein the driver circuit comprisesthin film transistors.
 11. The method according to claim 4 wherein thedriver circuit comprises thin film transistors.
 12. The method accordingto claim 7 wherein the driver circuit comprises thin film transistors.